Ultrastructure of Spermatozoa of Prionospio japonica (Annelida: Spionidae) from Taiwan
Vasily I. Radashevsky, Arkadiy A. Reunov, Olga V. Yurchenko, Yana N. Alexandrova, and Hwey-Lian Hsieh (2010) Prionospio japonica, a common inhabitant of estuaries in the northwestern Pacific Ocean, releases gametes into the water, where fertilization and planktotrophic larval development occur. Each spermatozoon has a biradially symmetrical acrosome 0.3 ± 0.1 μm long, a spherical nucleus 1.7 ± 0.2 μm in diameter, 4 spherical mitochondria 0.8 ± 0.1 μm in diameter, 2 centrioles situated perpendicular to each other, and a flagellum with a 9 × 2 + 2 organization of microtubules. The biradially symmetrical acrosome, which is also present in P. cf. queenslandica, is unique among polychaetes examined to date and possibly an apomorphy shared by a group of closely related Prionospio species.
Keywords
Sperm, Morphology, Polychaeta.
